This Program Project is aimed at understanding the mechanisms that control growth and multicellular development in Dictyostelium. By examining the functions of a large number of genes we will begin to formulate a global view of the regulatory networks In this organism. In the previous project period we took a functional genomics approach to high-throughput mutant phenotyping, using molecular barcodes, that has allowed us to draw functional inferences for hundreds of genes. We will revolutionize our parallel phenotyping platform using Next Generation Sequencing technologies that should yield dramatic improvements in barcode quantification so that more information can be gleaned from every new experiment. Over the next five years we will focus our efforts on understanding bacterial recognition in Dictyostelium, both during the growth of solitary amoebae and in the context of an innate immune response during development. We will define innate immune recognition of bacteria by amoebae in molecular terms by characterizing the genes and pathways involved. We will intersect the transcriptional profiling data from Project II with the physiological data provided by this project to uncover links between gene function and patterns of gene expression. The data we produce will also be used by Project 111 for extracting information about the genetic networks that coordinate bacterial recognition in Dictyostelium